Tropical rainforests

Question 1

Characteristics of a tropical climate

Answer 1

• Climate is consistent year round
• Average daily temp of 28C
• High precipitation—over 2000mm of rainfall annually
• No seasons

Question 2

Locations of tropical rainforests

Answer 2

1. AAS:
   - Asia: South & Southeast
   - Africa: West & Central
   - South & Central America
2. Tropics; places with high rainfall of >1500mm and temp of >20C

Question 3

Where are the tropics?

Answer 3

Between the Tropic of Cancer (23.5N) and the Tropic of Capricorn (23.5S)

Question 4

Characteristics of tropical rainforests (TBER)

Answer 4

• Thick & luxuriant evergreen forests
• Broad-leaved
• Evergreen trees
• Rich biodiversity

Question 5

Characteristics of evergreen trees

Answer 5

• Don’t shed their leaves all at once
• Continuously grow new leaves to replace old ones
• Dense foliage

Question 6

4 layers in a rainforest

Answer 6

Canopy layer, emergent layer, undergrowth layer, forest floor

Question 7

Characteristics of emergent layer

Answer 7

• Uppermost layer where some trees rise and tower above others
• It is formed by the crowns of those trees
• Can grow up to 50m-80m
• Trees usually have tall, straight & smooth trunks with few branches
• E.g. Kapok tree

Question 8

Characteristics of canopy layer

Answer 8

• Trees grow 20m-30m tall to reach for sunlight
• Trees grow close together, crowns interlock to form an almost continuous cover
• Blocks up to 90% sunlight from reaching forest floor
• “Pests” e.g. liana and epiphyte

Question 9

What are lianas

Answer 9

Thick, woody vines that twine up trees to reach for sunlight

Question 10

What are epiphytes

Answer 10

Plants that grow in trees to reach for sunlight, e.g. mosses & ferns

Question 11

Characteristics of undergrowth layer

Answer 11

• Dark; sunlight blocked by canopy layer
• Plants are small, thin and widely spaced due to lack of sunlight
• Plants have much larger leaves than those of other layers
• E.g. mosses, ferns

Question 12

Characteristics of forest floor

Answer 12

Thin layer of leaf litter due to rapid decomposition caused by hot and wet environment

Question 13

Living conditions in rainforests (HHDLS)

Answer 13

• High rainfall
• High temp
• Dark in the r=forest floor
• Lots of decomposition
• Still air
  High rainfall & high temp allow for a continuous growing season for plants and trees, causing the rainforest to be very dense and have many species of trees

Question 14

Adaptations of leaves in rainforests

Answer 14

• Broad leaves: helps trees capture more sunlight for photosynthesis
• Waxy, hairy or leathery surfaces: helps to minimise the loss of moisture through transpiration due to high temp
• Drip tips: narrow, downward-pointing tips of leaves that allow water to run off easily, preventing fungi& bacteria growth

Question 15

Adaptations of fruits & flowers in rainforests

Answer 15

Colourful and strong-smelling to attract insects or other animals for seed dispersal and pollination

Question 16

Adaptations of barks and branches in rainforests

Answer 16

• Tall, straight trunks
• Branches spread out near top 1/3 of tree helps tree to obtain max sunlight
• Smooth bark so rainwater flows easily from crown to root of tree
• Thin bark as no need for protection against cold/dry conditions

Question 17

Adaptations of roots in rainforests

Answer 17

• Buttress roots: grow from 1-5m above ground to help to support heavy weight of tall trees
• Shallow roots: to reach nutrients from rapid decomposition of leaves and branches which are mostly found at the top of the soil; water is available year-round so no need for roots to go deep in search of water